Conventional networking includes “static” configuration of services at various layers (e.g., Layer 0—optical, Layer 1—Time Division Multiplexing (TDM), Layer 2—packet, etc.). The optical layer can include circuit-based services, where network resources are dedicated to the circuit-based services. Networking planning efforts are utilized to change lower-layer services based on upper-layer demand, e.g., Layer 0 and/or 1 services changed based on packet demands. Some conventional attempts to automate this control or lower-layer services are accomplished with network resource broker and scheduler tools, but in this scenario, the bandwidth need is determined a priori and does not necessarily reflect actual usage. Conventional packet services are aggregated into circuit-oriented technologies (TDM), such as Optical Transport Network (OTN), where network resources are dedicated to particular connections, no matter the actual usage of the connections. This network paradigm has the following limitations: i) there is a waste of OTN resources when actual packet traffic is below OTN container size, ii) there can be dropping of packet traffic when the mapping is insufficient into the OTN container size, and iii) this leads to single-tiered pricing not based on actual usage of network.
Attempts to provide bandwidth-on-demand (BOD) in packet networks is traditionally accomplished with the use of Excess Information Rates (EIR) rates. If the network does not realize congestion, a user may be able to send extra packet data up to its EIR. However, there is no guarantee of EIR and customers' traffic may be dropped randomly in the case of oversubscription. In packet networking, with the reality of elephant and mouse flows and the realities of the TCP sliding window, inefficient traffic patterns may emerge. Elephant flows are extremely large continuous flows set up by a TCP (or other protocol) flow measured over a network link, and mouse flows are short (in total bytes) flows set up by a TCP (or other protocol) flow measured over a network link. Mouse flow bursts could have a detrimental effect on elephant flows causing throughput back-offs due to TCP sliding window, where if elephant flows had dedicated resources with less change of congestion, the elephant flows could complete faster. And vice-versa, in some circumstances, low-priority elephant flows may slow down the transmission of high-priority mouse flows in an unpredictable way.
Packet networking provides statistical multiplexing capabilities and can enforce Service Layer Agreements (SLAs) through Committed Information Rate (CIR) and EIR. But, in times of congestion, traffic oscillations may cause less-than-desired throughput within the network. Some attempts have been made to provide EIR-like functionality to circuit-based networks. But, these approaches are still somewhat “static” in nature, as they do not continually broker new EIR levels based on realized real-time analysis of the traffic. For example, some approaches in circuit-based networks include re-sizing OTN services in reaction to specific events like failures or over-subscription in new services. However, conventional approaches do not provide dynamic time-dependence.
Regarding packet networking, drawbacks include:                Packet queuing in times of congestion (when EIR traffic is being handled) can cause non-deterministic behavior on traffic flows. For instance, a burst of mouse flow traffic can cause packet loss to elephant flows, thus causing TCP sliding window behavior to impede throughput of the elephant flow;        Lack of tracking ongoing EIR consumption and relation back to a user, for consumption-based pricing models;        Lack of coordination of circuit-based, transport-layer services, so that OTN connections might be sized incorrectly for instantaneous use; and        All-packet solutions are not feasible, i.e., optical transport services are required for metro and core network connectivity. In addition, Layer 1 (e.g., OTN) networks provide cost savings relative to Multiprotocol Label Switching (MPLS) networks.        
Regarding OTN networks:                OTN networks are circuit-based. When an Optical channel Data Unit (ODU) is not being used to send traffic, the OTN resources are still active for the ODU and not available for any other connection; and        Proposed attempts to provide flexible ODU connection sizes are only effective at service creation time, and subsequently remain static, no matter their instantaneous utilization.        
Conventionally, in over-booking situations, network resources are not allocated by priority according to centralized network-wide logic. Furthermore, the process of prioritization does not have access to outside network information such as user's SLA and business priority in conventional approaches.
Regarding on-demand scheduling, in this model, something needs to notify the network a priori that additional bandwidth is required, and this may not always be a feasible determination.